Supernova

Interesting takes from Science News and Science Daily:

"shows that the accretion scenario, believed by many to be the most likely one, does not contribute more than a few percent to the observed type 1a supernova rate in [elliptical] galaxies"

Always nice when one's models are totally wrong. But never fear!

"the only viable alternative is the merger of two white dwarfs; therefore they are the likely cause of the majority of type 1a supernovae"

I can't imagine anything else, so the unlikely thing must be likely.

This is all related to the yardstick used to measure stellar distances.